// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002326/double-cos

​

// @nuget: Z.ExtensionMethods

​

using System;

public class Program

{

    public static void Main()

    {

        double[] doubles = { 0, 45, 90, 180 };

        foreach (double value in doubles)

        {

            double radians = (value * (Math.PI)) / 180;

            // C# Extension Method: Double - Cos

            Console.WriteLine("Cos({0}) = {1}", value, radians.Cos());

        }

    }

}